CN112011160B - High-toughness polymer-based temperature-sensitive composite material and preparation method and application thereof - Google Patents
High-toughness polymer-based temperature-sensitive composite material and preparation method and application thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of polymer conductive composite materials, and particularly relates to a high-toughness high-sensitivity polymer-based temperature-sensitive composite material and a preparation method and application thereof. The invention provides a high-toughness polymer-based temperature-sensitive composite material, which comprises a polymer matrix and a conductive filler, wherein the conductive filler forms a conductive network in the polymer matrix, and the conductive network is a three-dimensional conductive network formed by a one-dimensional conductive filler and a two-dimensional conductive filler; the conductive filler accounts for 0.1-5 w% of the mass of the high-toughness temperature-sensitive composite material, and the mass ratio of the one-dimensional conductive filler to the two-dimensional conductive filler in the conductive filler is 1:1. The flexible strain sensor prepared by the method has high strength, high toughness and high sensitivity; the experimental method is simple and different, can obviously improve the effective utilization rate of the monomer, is convenient for industrial production, and expands the application field of the monomer.
Description
Technical Field
The invention belongs to the technical field of polymer conductive composite materials, and particularly relates to a high-toughness high-sensitivity polymer-based temperature-sensitive composite material and a preparation method and application thereof.
Background
The temperature-sensitive sensor is mainly prepared from metal or metal oxide semiconductor, has high sensitivity to temperature change, but has poor stability and complex processing, cannot bear large strain, and is easy to damage under external force impact.
The prior art reports that high-molecular-weight Conductive Polymers (CPCs) can be used as a temperature-sensitive sensor, and the high-molecular-weight Conductive Polymers (CPCs) are formed by doping conductive particles such as metal powder, graphite, CB and carbon nanotubes into an organic polymer serving as a matrix, so that the heat-sensitive performance of the sensor can be improved to a certain extent; the CPCs exhibit positive temperature coefficient characteristics (PTC) and negative temperature coefficient characteristics (NTC) under the action of a temperature field, the PTC effect means that the conductivity of the polymer conductive composite decreases with increasing temperature, and the NTC effect means that the conductivity of the polymer conductive composite increases with increasing temperature. In the current research on the polymer-based conductive composite material, the PTC effect is often shown by adding graphene, multi-walled carbon nanotubes or metal powder and the like, and the temperature response time is slow, so that the application prospect of the conductive polymer composite material is greatly limited.
Disclosure of Invention
Aiming at the defects, the invention provides a flexible strain sensor with high toughness and high sensitivity and a preparation method thereof, and the flexible strain sensor such as a polylactic acid product prepared by the method has high strength, high toughness and high sensitivity; the experimental method is simple and different, can obviously improve the effective utilization rate of the monomer, is convenient for industrial production, and expands the application field of the monomer.
The technical scheme of the invention is as follows:
the first technical problem to be solved by the invention is to provide a high-toughness polymer-based temperature-sensitive composite material, which comprises a polymer matrix and a conductive filler, wherein the conductive filler forms a conductive network in the polymer matrix, and the conductive network is a three-dimensional conductive network formed by a one-dimensional conductive filler and a two-dimensional conductive filler; the conductive filler accounts for 0.1-5 w% of the mass of the high-toughness temperature-sensitive composite material, and the mass ratio of the one-dimensional conductive filler to the two-dimensional conductive filler in the conductive filler is 1:1.
Further, the polymer matrix is at least one of polylactic acid (PLA), polybutylene succinate (PBS) or polybutylene terephthalate-adipate (PBAT); preferably polylactic acid.
Further, when the polymer matrix is polylactic acid, the polylactic acid is modified polylactic acid, and the modified polylactic acid is prepared by the following method: carrying out melt processing on polylactic acid by dicumyl peroxide (DCP) and polyethylene glycol diacrylate (PEGDA) at 180-200 ℃ for 5-10 min to carry out branching reaction; wherein the proportion of each raw material is as follows: 100 parts of polylactic acid, 0.25 part of dicumyl peroxide (DCP) and 0.05-0.5 part of polyethylene glycol diacrylate (PEGDA).
Further, the one-dimensional conductive filler is at least one of a multi-walled carbon nanotube, a single-walled carbon nanotube or a carbon fiber.
Further, the two-dimensional conductive filler is at least one of graphene nanoplatelets, graphene or graphite.
The second technical problem to be solved by the present invention is to provide a preparation method of the high-toughness polymer-based temperature-sensitive composite material, wherein the preparation method comprises: the one-dimensional conductive filler and the two-dimensional conductive filler are taken as composite conductive fillers and are melted and blended with the polymer matrix at the temperature higher than the melting point of the polymer matrix and lower than the thermal decomposition temperature of the polymer matrix.
Further, the melt blending temperature is 180-200 ℃, and the blending time is 5-8 min.
The third technical problem to be solved by the invention is to provide a flexible temperature-sensitive sensor, which is prepared from the polymer-based temperature-sensitive composite material.
The fourth technical problem to be solved by the present invention is to provide a method for reducing the conductive percolation value of a high polymer material, wherein the method comprises: simultaneously introducing a one-dimensional conductive filler and a two-dimensional conductive filler into a high polymer material, namely melting and blending the high polymer material, the one-dimensional conductive filler and the two-dimensional conductive filler; the mass ratio of the conductive filler to the high polymer material is as follows: 0.5wt% to 3wt%:99.5wt% -97 wt%, wherein the mass ratio of the one-dimensional conductive filler to the two-dimensional conductive filler in the conductive filler is 1:1.
Further, the high polymer material is at least one of polylactic acid (PLA), polybutylene succinate (PBS) or polybutylene terephthalate-adipate (PBAT); preferably polylactic acid.
Further, when the polymer matrix is polylactic acid, the polylactic acid is modified polylactic acid, and the modified polylactic acid is prepared by adopting the following method: carrying out melt processing on polylactic acid by dicumyl peroxide (DCP) and polyethylene glycol diacrylate (PEGDA) at 180-200 ℃ for 5-10 min to carry out branching reaction; wherein the proportion of each raw material is as follows: 100 parts of polylactic acid, 0.25 part of dicumyl peroxide (DCP) and 0.05-0.5 part of polyethylene glycol diacrylate (PEGDA).
Further, the one-dimensional conductive filler is at least one of a multi-walled carbon nanotube, a single-walled carbon nanotube or a carbon fiber.
Further, the two-dimensional conductive filler is at least one of graphene nanoplatelets, graphene or graphite.
The fifth technical problem to be solved by the present invention is to provide a composite material having both NTC effect and PTC effect (i.e. a composite material integrating NTC and PTC effect), wherein the composite material comprises a polymer matrix and a conductive filler, the conductive filler forms a conductive network in the polymer matrix, and the conductive network is a three-dimensional conductive network formed by a one-dimensional conductive filler and a two-dimensional conductive filler; the conductive filler accounts for 0.1-5 w% of the mass of the high-toughness temperature-sensitive composite material, and the mass ratio of the one-dimensional conductive filler to the two-dimensional conductive filler in the conductive filler is 1:1.
The sixth technical problem to be solved by the present invention is to provide a preparation method of the above composite material having both NTC effect and PTC effect, wherein the preparation method comprises: the one-dimensional conductive filler, the two-dimensional conductive filler and the polymer matrix are melted and blended at a temperature higher than the melting point of the polymer matrix and lower than the thermal decomposition temperature.
The invention has the beneficial effects that:
1) The polymer-based temperature-sensitive material prepared by the method overcomes the defects of low toughness and strength of polymer substrates such as polylactic acid, and greatly expands the application field of bio-based polymer materials; through the construction of the three-dimensional conductive network, the temperature response speed, the repeatability and the flexibility of the polymer-based temperature-sensitive material can be remarkably improved, and the problems of poor biocompatibility, low mechanical strength, low sensitivity and repeatability and the like of the traditional sensor are solved.
2) When the modified polylactic acid is selected as a matrix, the DCP can promote the linear polylactic acid to be decomposed to generate unstable tertiary carbon free radicals, and the unstable tertiary carbon free radicals can generate a branching reaction with the polyethylene glycol diacrylate under the action of the DCP, so that the strength can be improved, and the toughness of the material can be improved; the solution-melting method is adopted, the dispersion of conductive ions in a matrix can be obviously improved, and the polymer-based temperature-sensitive material prepared by the method has a low percolation value of the conductive filler; the method is simple to operate, the conductive filler is low in price, and the method is suitable for large-scale production.
3) The polymer-based temperature-sensitive material prepared by the invention has degradability, can be self-decomposed under natural conditions, and plays a role in environmental friendliness and acid and alkali corrosion resistance.
4) Compared with other polymer-based temperature-sensitive materials, the polymer-based temperature-sensitive material prepared by the invention has better toughness, temperature sensitivity and repeatability, so that the polymer-based temperature-sensitive material prepared by the invention can be widely applied to the fields of medicine, human health monitoring, wearable equipment and the like.
Drawings
FIGS. 1 (a) and 1 (b) are graphs showing the change with time of the extensional viscosity of the materials obtained in examples 1 and 2, respectively.
FIG. 2 is a TEM image of the material obtained in example 7.
FIG. 3 is a graph showing the change in conductivity of the composite materials obtained in examples 5 to 12 and comparative examples 1 to 13.
FIG. 4 is a graph of the change in conductivity of the composite materials obtained in example 7, comparative example 1, and comparative example 11 during a single ramping.
The specific implementation mode is as follows:
in the invention, the response principle of the polymer matrix/conductive filler temperature-sensitive sensor to temperature is as follows: firstly, the conductive fillers interact with each other, and the resistance of a single conductive filler per se is reduced along with the increase of the temperature, and secondly, as the conductive network structure formed in the invention is a three-dimensional conductive network structure formed by one-dimensional conductive fillers and two-dimensional conductive fillers, the surface of the conductive filler can fluctuate in the temperature increase process, so that the contact rate between the conductive fillers is increased, and the resistance is changed.
The following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.
Example 1
1) Drying PLA granules at 70 ℃ in vacuum for 24 hours; placing 100 parts by weight of PLA into an internal mixer for blending, wherein the blending time is 5min, the rotating speed is 50rpm, and the processing temperature is 180 ℃;
2) To verify that polylactic acid was injection molded after processing modification using a HAAKE MiniJet Pro mini injection molding machine: the injection pressure is 450bar, the melt temperature is 180 ℃, and the mold temperature is 100 ℃; the samples were subjected to mechanical property tests, and the results are shown in table 1.
Example 2
1) Drying PLA granules at 70 ℃ in vacuum for 24 hours; mixing 100 parts by weight of PLA, 0.3 part by weight of DCP and 0.2 part by weight of PEGDA in an internal mixer for 5min at the rotation speed of 50rpm and the processing temperature of 180 ℃;
2) To verify that polylactic acid was injection molded after processing modification using a HAAKE MiniJet Pro mini injection molding machine: the injection pressure is 450bar, the melt temperature is 180 ℃, and the mold temperature is 100 ℃; the samples were subjected to mechanical property tests, and the results are shown in table 1.
Example 3
1) Drying PLA granules at 70 ℃ in vacuum for 24 hours; mixing 100 parts by weight of PLA, 0.3 part by weight of DCP and 0.4 part by weight of PEGDA in an internal mixer for 5min at the rotation speed of 50rpm and the processing temperature of 180 ℃;
2) To verify that polylactic acid was injection molded after processing modification using a HAAKE MiniJet Pro mini injection molding machine: the injection pressure is 450bar, the melt temperature is 180 ℃, and the mold temperature is 100 ℃; the samples were subjected to mechanical property tests, and the results are shown in table 1.
Example 4
1) Drying PLA granules at 70 ℃ in vacuum for 24 hours; according to 100 parts by weight of PLA, 0.3 part by weight of DCP and 0.5 part by weight of PEGDA are put into an internal mixer for blending, the blending time is 5min, the rotating speed is 50rpm, and the processing temperature is 180 ℃;
2) To verify that polylactic acid was injection molded after processing modification using a HAAKE MiniJet Pro mini injection molding machine: the injection pressure is 450bar, the melt temperature is 180 ℃, and the mold temperature is 100 ℃; the samples were subjected to mechanical property tests, and the results are shown in table 1.
TABLE 1 comparison of mechanical Properties of samples obtained in examples 1 to 4
| Tensile Strength (MPa) | Elongation at Break (%) | |
| Example 1 | 64.8 | 20.5 |
| Example 2 | 66.4 | 17.5 |
| Example 3 | 72.5 | 31.4 |
| Example 4 | 75.4 | 34.6 |
Through the data analysis in table 2, the modified polylactic acid with the preferred PEGDA content of 0.4 weight part is used for preparing the polymer-based temperature-sensitive material: dispersing conductive filler in an organic solvent at room temperature, performing ultrasonic treatment for 60-90 min to obtain a dispersion liquid of the conductive filler, then adding PLA into the conductive dispersion liquid, stirring for 60-80 min to obtain a polymer/conductive filler dispersion liquid, performing ultrasonic dispersion at 70-90 ℃ until the organic solvent is volatilized, transferring the organic solvent into a vacuum oven at 60-80 ℃ for drying treatment, and finally performing melt blending, pressing, cooling and demolding on the pre-blended material to obtain the polymer-based temperature-sensitive material.
Example 5
1) The proportions of the raw materials are shown in Table 2;
2) Firstly, LCBPLA granules are dried and dried in vacuum at 70 ℃ for 24h, and the preparation of the LCBPLA/MWCNTs-GnPs temperature-sensitive material comprises the following steps: firstly, dispersing MWCNTs-GnPs in acetone according to the proportion in the table 2, and performing ultrasonic dispersion for 60-90 min to obtain a MWCNTs-GnPs dispersion liquid. And then adding LCBPLA into the dispersion liquid, mechanically stirring for 60min, then performing ultrasonic dispersion at the temperature of 70-90 ℃ until the solvent is completely volatilized, transferring the mixture into a vacuum oven at the temperature of 60-80 ℃ for drying treatment, and finally putting the pre-blend into a torque rheometer for processing, wherein the processing temperature is 180 ℃, the rotation speed is 50rpm, and the processing time is 5min.
3) Hot-press molding: preheating the blend obtained in the step 2) at 180 ℃ for 5min, then maintaining the pressure at 10MPa for 5min, and then cooling to room temperature at 5MPa to obtain the required polymer temperature-sensitive material.
It should be noted that the weight ratio of MWCNTs/GnPs in the above mixture ratio is 1:1.
The formulations of examples 6-10 are shown in Table 2 and were prepared in the same manner as in example 5.
Table 2 raw materials formulation table for examples 6-10
| Examples | LCBPLA | MWCNTs-GnPs | MWCNTs-GnPs mass fraction (wt%) |
| 6 | 99.5 | 0.5 | 0.5％ |
| 7 | 99.4 | 0.6 | 0.6％ |
| 8 | 99.2 | 0.8 | 0.8％ |
| 9 | 99 | 1 | 1％ |
| 10 | 98 | 2 | 2％ |
| 11 | 97.5 | 2.5 | 2.5％ |
| 12 | 97 | 3 | 3％ |
Comparative example 1
1) The proportions of the raw materials are shown in Table 3;
2) Firstly, LCBPLA granules are dried and dried in vacuum at 70 ℃ for 24h, and the preparation of the LCBPLA/MWCNTs temperature-sensitive material comprises the following steps: firstly, MWCNTs are dispersed in acetone according to the proportion in the table 2, and the MWCNTs dispersion liquid is obtained after ultrasonic dispersion for 60-90 min. And then adding LCBPLA into the dispersion liquid, mechanically stirring for 60min, then performing ultrasonic dispersion at the temperature of 70-90 ℃ until the solvent is completely volatilized, transferring the mixture into a vacuum oven at the temperature of 60-80 ℃ for drying treatment, and finally putting the pre-blend into a torque rheometer for processing, wherein the processing temperature is 180 ℃, the rotation speed is 50rpm, and the processing time is 5min.
3) Hot-press molding: preheating the blend obtained in the step 2) at 180 ℃ for 5min, then maintaining the pressure at 10MPa for 5min, and then cooling to room temperature at 5MPa to obtain the required polymer temperature-sensitive material.
The formulations of comparative examples 2 to 6 are shown in Table 3, and the preparation methods are the same as in comparative example 1.
TABLE 3 formulation tables for comparative examples 2-6
| Comparative example | LCBPLA | MWCNTs | MWCNTs mass fraction (wt%) |
| 1 | 99.5 | 0.5 | 0.5％ |
| 2 | 99.3 | 0.7 | 0.7％ |
| 3 | 99.2 | 0.8 | 0.8％ |
| 4 | 99 | 1 | 1％ |
| 5 | 98 | 2 | 2％ |
| 6 | 97.5 | 2.5 | 2.5％ |
Comparative example 7
1) The proportions of the raw materials are shown in Table 4;
2) Firstly, drying LCBPLA granules at 70 ℃ in vacuum for 24h, and preparing the LCBPLA/GnPs temperature-sensitive material: firstly, MWCNTs are dispersed in acetone according to the proportion in the table 2, and are subjected to ultrasonic dispersion for 60-90 min to obtain GnPs dispersion liquid. And then adding LCBPLA into the dispersion liquid, mechanically stirring for 60min, then performing ultrasonic dispersion at the temperature of 70-90 ℃ until the solvent is completely volatilized, transferring the mixture into a vacuum oven at the temperature of 60-80 ℃ for drying treatment, and finally putting the pre-blend into a torque rheometer for processing, wherein the processing temperature is 180 ℃, the rotation speed is 50rpm, and the processing time is 5min.
3) Hot-press molding: preheating the blend obtained in the step 2) at 180 ℃ for 5min, then maintaining the pressure at 10MPa for 5min, and then cooling to room temperature at 5MPa to obtain the required polymer temperature-sensitive material.
The formulations of comparative examples 7 to 10 are shown in Table 4, and the preparation methods are the same as in comparative example 1.
TABLE 4 raw material formulation tables for comparative examples 7 to 10
| Comparative example | LCBPLA(g) | GnPs(g) | Mass fraction (wt%) of GnPs |
| 7 | 99 | 1 | 1％ |
| 8 | 98 | 2 | 2％ |
| 9 | 97.5 | 2.5 | 2.5％ |
| 10 | 97 | 3 | 3％ |
| 11 | 96.5 | 3.5 | 3.5％ |
| 12 | 96 | 4 | 4％ |
| 13 | 95 | 5 | 5％ |
And (3) performance testing:
in order to investigate the formation of the long-chain structure, examples 1 and 2 were subjected to dynamic rheology tests, and the extensional flow characteristics of the modified polylactic acid when it was stretched in a molten state were investigated using an ARES rheometer fixed to an Extensional Viscosity Frame (EVF) in which the extensional viscosity changes the formation of long-chain branches with respect to shear flowIs sensitive. In particular, at a certain strain, with an increase in transient viscosity, a strain hardening behavior can be observed, which can be used to characterize the formation of long branched structures. FIG. 1a shows the shear rate at various shear rates from 0.02 to 0.5s -1 Lower extensional viscosity curve, it can be seen that the strain softening behavior is such that the extensional viscosity increases and then decreases at the beginning of the extension. This phenomenon is due to the lack of long-branched structure in these samples. Whereas in FIG. 1b a certain degree of strain hardening is shown, the occurrence of this phenomenon requires more than 2 branching points on the branched chain, indicating the formation of a long branched chain structure.
FIG. 2 is a TEM image of example 7 of the present invention, in which the white regions are the PLA matrix and the black regions are the conductive fillers. As can be seen from the figure, the one-dimensional MWCNTs are distributed on the surface of the two-dimensional GnPs, so that a three-dimensional conductive network structure is formed.
And (3) testing electrical properties: in order to examine the conductivity of the composite material of the present invention, a conductivity test was performed on 10mm × 30mm × 0.5mm samples prepared in examples and comparative examples using a homoeographic resistance meter TH2684A (yokogaku corporation, yokogaku), and the results are shown in fig. 2. From the figure, the percolation values of the MWCNTs and the GnPs which are respectively added into the long-chain branched polylactic acid matrix are respectively 0.63 and 3.2, and after the MWCNTs and the GnPs are compounded, the percolation value of the composite material is obviously reduced to about 0.52, which fully embodies that the percolation value of the composite material can be obviously reduced by the method adopted by the invention.
Temperature-resistance test: in order to examine the temperature-sensitive characteristic of the composite material, a Teck DMM4050 is adopted to carry out temperature-resistance test on the examples and the comparative examples, and the change of resistance is recorded in real time, wherein the heating rate is 2 ℃/min, and the temperature interval is 40 ℃ to 180 ℃. The data were processed to obtain a conductivity change (conductivity/initial conductivity) curve, as shown in fig. 4. It is clear from the figure that when the MWCNTs and GnPs are added separately, the composite material shows a phenomenon of conductivity reduction along with the increase of temperature, which is called PTC effect, while after the MWCNTs and the GnPs are added simultaneously, a certain PTC effect and NTC effect are shown, and the change value of the conductivity is more greatly changed by 0.6 percent compared with that of MWCNTs-GnPs/LCBPLA, which indicates that the composite material is more sensitive to the temperature.
Mechanical property analysis: the examples and comparative examples were subjected to mechanical property tests as shown in table 5. The data in the table are compared to find that the tensile strength and the elongation at break of the composite material can be improved by the formation of the long branched chain structure, and the toughness and the strength of the composite material can be further improved after the MWCNTs-GnPs are introduced into the composite material.
TABLE 5 structural comparison of tensile Properties and elongations at break of the samples obtained in examples 1-11
| Tensile Strength (MPa) | Elongation at Break (%) | |
| Example 1 | 64.8 | 20.5 |
| Example 4 | 75.4 | 34.6 |
| Example 6 | 78.6 | 32.5 |
| Example 7 | 82.4 | 34.6 |
| Example 8 | 83.3 | 42.1 |
| Example 9 | 79.1 | 33.2 |
| Example 10 | 68.6 | 26.8 |
| Example 11 | 62.1 | 22.4 |
| Example 11 | 54.9 | 12.8 |
The experiment shows that the preparation method of the conductive composite material provided by the invention is simple, and the conductive composite material has higher strength and toughness, higher response speed to temperature and higher stability, so that the conductive composite material can be used as a temperature sensor with excellent performance. The MWCNTs, gnPs and the polymer composite material can endow the bio-based polymer material with good toughness and biodegradability, and can resist corrosion in the environment. The preparation method is simple and quick, and saves cost.
Claims (3)
1. A method for reducing the conductive percolation value of a high polymer material is characterized by comprising the following steps: simultaneously introducing a one-dimensional conductive filler and a two-dimensional conductive filler into the modified polylactic acid, namely melting and blending the modified polylactic acid, the one-dimensional conductive filler and the two-dimensional conductive filler; wherein the mass ratio of the conductive filler to the modified polylactic acid is as follows: 0.5wt% -3 wt%: 99.5-97 wt%, wherein the mass ratio of the one-dimensional conductive filler to the two-dimensional conductive filler in the conductive filler is 1:1; the modified polylactic acid is prepared by the following method: carrying out a branching reaction by melting and processing the polylactic acid with dicumyl peroxide and polyethylene glycol diacrylate at 180-200 ℃ for 5-10min; wherein the proportion of each raw material is as follows: 100 parts of polylactic acid, 0.25 part of dicumyl peroxide and 0.05-0.5 part of polyethylene glycol diacrylate.
2. The method for reducing the conductive percolation value of the high molecular material according to claim 1, wherein the one-dimensional conductive filler is at least one of multi-walled carbon nanotubes, single-walled carbon nanotubes or carbon fibers;
the two-dimensional conductive filler is at least one of graphene micro-sheets, graphene or graphite.
3. The method for reducing the conductive percolation value of the high polymer material according to claim 1 or 2, wherein the melt blending temperature is 180-200 ℃, and the blending time is 5-8min.
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| CN101597396A (en) * | 2009-07-02 | 2009-12-09 | 浙江华源电热有限公司 | Polymer-based positive temperature coefficient thermistor material |
| CN105907009A (en) * | 2016-05-18 | 2016-08-31 | 郑州大学 | Preparation of conductive high polymer composite material and application of conductive high polymer composite material in strain sensor |
| CN106046721A (en) * | 2016-05-30 | 2016-10-26 | 郑州大学 | High-polymer based temperature-sensitive material and preparation method and application thereof |
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| CN110408039A (en) * | 2019-08-19 | 2019-11-05 | 陕西理工大学 | A kind of preparation method of the miniature product of high-intensity and high-tenacity polylactic acid |
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| CN101597396A (en) * | 2009-07-02 | 2009-12-09 | 浙江华源电热有限公司 | Polymer-based positive temperature coefficient thermistor material |
| CN105907009A (en) * | 2016-05-18 | 2016-08-31 | 郑州大学 | Preparation of conductive high polymer composite material and application of conductive high polymer composite material in strain sensor |
| CN106046721A (en) * | 2016-05-30 | 2016-10-26 | 郑州大学 | High-polymer based temperature-sensitive material and preparation method and application thereof |
| CN107602987A (en) * | 2017-10-10 | 2018-01-19 | 上海第二工业大学 | The high molecular PTC composite and preparation method of a kind of graphene-containing and CNT |
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